The present invention relates to a rotary knife and more particularly to a rotary knife having an annular blade supported in a generally circular blade housing for rotation about a central axis.
Power operated knives having annular blades supported for rotation in a groove formed in an annular blade housing are in widespread use for cutting meat. These knives have been subject to problems resulting from fat being deposited within the grooves between the blades and the blade housings. Fat that is present in the meat is often pressed into the juncture of the rotating blade and the blade housing as the knife is used to trim meat. The fat is swept away by the rotating blade, softens, and becomes fluent when exposed to heat generated by the blade. The fluent fat is swept into the narrow space between the radially outer blade periphery and the adjacent radially outer blade groove wall, from which escape is difficult. Blade friction continues to heat the fluent fat in the blade groove eventually transforming it into a varnish-like film that interferes with knife operation by creating more friction and heat. Consequently the knives must be taken out of service so that the fat deposits may be removed.
The prior art knives have been provided with lubrication systems by which the knife operator can introduce an edible lubricant into the blade housing for the purpose of reducing friction and concomitant heating. The quantity of lubricant supplied to the knives has not been easily controlled. When excessive amounts have been introduced, the lubricant itself has become overheated, turned into a varnish-like coating and exacerbated the heating problems by increasing the blade friction.
Rotary knives that have annular blades supported by blade housings for rotation about a central axis have been constructed in the past with different schemes for enabling blade removal and replacement. In some cases, the blade housing was annular, split member that supported a continuous annular blade member in a groove that opened radially inwardly toward the blade rotation axis. The blade housing was resiliently expanded by spreading its split ends far enough apart to permit removal and replacement of the continuous annular blade. Many knives of this construction required the operator to manually grip the blade housing while spreading its ends. In other constructions the blade housings were provided with tool receiving slots so that a screw driver or similar tool could be inserted in the slot and used to pry the blade housing ends apart. These approaches tended to be unwieldy, particularly where a single operator had to hold the knife and maintain the blade housing expanded while trying to insert a blade into the blade housing. When operators did not wear prescribed cut resistant gloves, hand cuts could result.
The present invention provides a new and improved rotary knife that is so constructed and arranged that fluent fatty material accumulating between the blade and the blade housing groove is directed out of the blade housing. The invention also provides a new and improved rotary knife wherein the blade may be removed from a split blade housing and replaced without requiring the operator to separate the blade housing ends by hand or by using a hand tool.
The present invention provides a new and improved rotary knife having a blade housing and an annular blade supported by the blade housing for rotation about a central axis The blade defines a body section supported by the blade housing and a blade section that extends axially from the body section and projects from the blade housing. The blade housing comprises a ring-like member having an annularly extending blade supporting groove that opens radially inwardly and in which the blade is rotatably disposed. The groove is defined by axially spaced apart first and second walls and a peripheral wall located between the first and second walls. The peripheral wall defines a plurality of blade engaging bearing faces spaced apart throughout the blade housing periphery and a plurality of circumferentially spaced apart fat receiving recesses. The blade housing also defines a plurality of fat directing channels each communicating with a fat receiving recess for directing fat from the recess out of the blade housing.
In an illustrated embodiment one of the first and second axially spaced walls defines the fat directing channels with the channels axially aligned with the respective recesses.
According to another feature of the invention a rotary knife is provided that comprises a handle, a split blade housing that comprises a ring-like member supported by the handle and defining a circumferentially extending groove, an annular blade supported in the blade housing groove for rotation about a central axis, and a manually actuated mechanism for adjustably changing the width of the split to enable removal of the blade. The split blade housing has end portions on opposite sides of the split that are detachably connected to the handle. The mechanism comprises a first element movably supported by the handle and a second element fixed with respect to an end portion of the blade housing, the first and second elements reacting to expand and contract the split.
In an illustrated embodiment the first and second elements are gears.
Additional features of the invention will become apparent from the following detailed description made with reference to the accompanying drawings.